docs: def on_connection_blocked(self, method_frame):
          """This method is called by pika if RabbitMQ sends a connection blocked
          method, to let us know we need to throttle our publishing.
  
          :param pika.amqp_object.Method method_frame: The blocked method frame
  
          """
          LOGGER.warning('Connection blocked: %s', method_frame)
          self.state = self.STATE_BLOCKED
          if self.on_unavailable:
              self.on_unavailable(self)